I fell off my bike a couple of weeks ago and since then my shoulder causes me too much pain when I cycle. I have started walking for an hour a day to make sure I get some exercise until I can get back on the bike. I have read quite a bit over the years about walking, and it is generally considered to be very good for you and with enough of it you can lose weight. Although it is some time since I read about it and therefore my recollection is hazy I recall reading that it is not as straightforward as the more calories you burn resulting in proportionally more weight loss.
Whilst you will burn more calories per time unit when cycling than you do when walking, there is a heart rate range that causes your body to burn fat more efficiently (i think it is up to about 75% of you maximum heart rate, although I would have to go back and check). Not all calories that you burn are fat, some can be food and muscle tissue. When cycling, especially when pedalling hard, you will almost certainly exceed that rate, so you won't burn the same proportion of fat calories. You will probably burn far more calories overall when cycling including a lot of fat ones, but walking is good for weight loss if you are prepared to put the time in.